Registration number was HS-231. Our registration system (Aussie) is State by State based and, several years ago, the two letters/three numbers series was coming to the ZZ-000 situation. The Registration Authority decided they has enough expired/cancelled plates from the ‘50’s, 60’s and ‘70’s, so started to re-use old ones.
Last time I checked, HS-231 was on an early 2000’s HD. Checked just now and it’s available again. We can buy ‘re-issue’ plates, so maybe I should get it for my S1 I hope to pick up soon.
Bought my H1-B in '86; S3 about '88; and H2-A about '91.
Jeff